1. Field of the Invention
The present invention refers to cores used for the winding and rewinding of products in the paper, textile, plastic and metal industries, and to core and shaft assemblies used in turn up operations in the papermaking industry.
2. Related Art
A wide variety of core and shaft assemblies are used in winding and storing products. It is common practice to use a fiber core and a pneumatically expandable shaft such as those manufactured by Tideland or Doublin which are high maintenance items requiring high initial costs. Fiber cores, however, have a relatively short lifetime and also have a tendency to absorb moisture from the air. This process can weaken the core and prevent proper operation of the shaft core assembly particularly where close tolerances are required. Finally, the core and shaft should be a self-locking assembly that provides for a minimal chance of slippage between the two under heavy loads. Improvements are needed in the prior art apparatus.